U.S. patent number 9,816,768 [Application Number 15/200,639] was granted by the patent office on 2017-11-14 for gas-operated firearm with pressure compensating gas piston.
This patent grant is currently assigned to RA Brands, L.L.C.. The grantee listed for this patent is RA Brands, L.L.C.. Invention is credited to Jonathan Ricks.
United States Patent |
9,816,768 |
Ricks |
November 14, 2017 |
Gas-operated firearm with pressure compensating gas piston
Abstract
A firearm may have gas operating system that renders the firearm
capable of firing a wide range of shot loads by passively or
automatically compensating for different shot loads. The firearm
may include a plurality of ports formed in the firearm barrel, and
corresponding ports formed in a gas block of the gas operating
system. The ports tap gases generated during firing which are used
to cycle the firearm. When firing different cartridge loads,
differing combinations of the ports are selectively at least
partially blocked or otherwise obstructed by the cartridge casing
according to the size of the cartridge. Additionally, the gas
operating system includes compensating gas pistons with internal
relief valves that can bleed off excess gas to compensate for
larger shot loads regardless of the size of the cartridge.
Inventors: |
Ricks; Jonathan (Harvest,
AL) |
Applicant: |
Name |
City |
State |
Country |
Type |
RA Brands, L.L.C. |
Madison |
NC |
US |
|
|
Assignee: |
RA Brands, L.L.C. (Madison,
NC)
|
Family
ID: |
55525453 |
Appl.
No.: |
15/200,639 |
Filed: |
July 1, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170089652 A1 |
Mar 30, 2017 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
14803624 |
Jul 20, 2015 |
9383149 |
|
|
|
13799786 |
Aug 4, 2015 |
9097475 |
|
|
|
61797420 |
Dec 5, 2012 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F41A
5/26 (20130101); F41A 3/66 (20130101); F41A
5/28 (20130101); F41A 21/28 (20130101); F41A
3/12 (20130101); F41A 5/22 (20130101) |
Current International
Class: |
F41A
5/26 (20060101); F41A 5/22 (20060101); F41A
3/66 (20060101); F41A 3/12 (20060101); F41A
5/28 (20060101); F41A 21/28 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0158707 |
|
Oct 1985 |
|
EP |
|
WO 2010/123604 |
|
Oct 2010 |
|
WO |
|
Other References
Jacob Gottfredson, Standing ready: Sig Sauers 516 patrol rifle,
Guns Magazine, Mar. 1, 2012, pp. 68-70, vol. 58, issue 3,
Publishers Development Coporation. cited by applicant .
Michael O. Humphries, SIG Sauer SIG556 Classic, Aug. 23, 2012, 2
pages, National Rifle Association,
http://www.americanrifleman.org/ArticlePage.aspx?id=1661&cid=4.
cited by applicant .
International Search Report dated Jul. 9, 2014 for International
Application No. PCT/US20132/072674 filed Dec. 2, 2013. cited by
applicant .
Written Opinion dated Jul. 9, 2014 for International Application
No. PCT/US2013/072674 filed Dec. 2, 2013. cited by
applicant.
|
Primary Examiner: Johnson; Stephen
Attorney, Agent or Firm: Womble Carlyle Sandridge &
Rice, LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
The present Patent Application is a continuation of U.S. patent
application Ser. No. 14/803,624, filed Jul. 20, 2015, which issued
on Jul. 5, 2016 as U.S. Pat. No. 9,383,149, and which is a
continuation-in-part of previously filed, co-pending U.S. patent
application Ser. No. 13/799,786, filed Mar. 13, 2013, which issued
on Aug. 4, 2015 as U.S. Pat. No. 9,097,475, and which is a
formalization of previously-filed U.S. Provisional Patent
Application Ser. No. 61/797,420, filed Dec. 5, 2012. This Patent
Application accordingly claims the benefit of the filing date of
the above-cited United States Utility and Provisional Patent
Applications according to the statutes and rules governing
continuations and provisional patent applications, particularly 35
U.S.C. .sctn.120 and 37 C.F.R. .sctn.1.78(a)-(c). The specification
and drawings of the United States Provisional Patent Applications
referenced above are specifically incorporated herein by reference
as if set forth in their entirety.
Claims
What is claimed is:
1. An auto-loading firearm for firing cartridges of different
lengths and/or varying load strengths, comprising: a receiver; a
barrel mounted to a forward end of the receiver, the barrel
comprising a series of gas ports arranged at spaced locations
therealong, and a chamber located at a proximal end of the barrel
to receive cartridges for firing; a bolt assembly translatable
along the receiver for loading cartridges into the chamber and
ejecting spent casings from the firearm after firing; and a gas
operating system that drives movement of the bolt assembly along
the receiver, the gas operating system comprising: a gas cylinder
having a longitudinal piston bore, and one or more ports in fluid
communication with the piston bore and at least one of the series
of gas ports of the barrel for passage of pressurized gases
generated during firing into the piston bore; a gas piston disposed
within and movable along the piston bore, the gas piston
operatively connected to the bolt assembly such that the
pressurized gases passing into the piston bore and driving the gas
piston therealong cause the bolt assembly to be driven along the
receiver for cycling the firearm; and a gas relief valve integrated
within the gas piston and movable therealong as a pressure of the
pressurized gases exceeds a desired operating level to enable
excess gases impinging on the gas piston to escape through the gas
piston and reduce pressure acting on thereon to control velocity of
the bolt assembly as it moves during cycling of the firearm.
2. The firearm of claim 1, wherein the gas relief valve comprises a
valve housing, a valve bore at least partially defined by the valve
housing, and a valve member at least partially disposed within and
movable along the valve bore.
3. The firearm of claim 2, wherein the gas relief valve further
comprises a valve inlet in fluid communication with the valve bore
and the piston bore, and wherein the valve member is substantially
biased toward a position at least partially closing the valve
inlet.
4. The firearm of claim 3, wherein the gas piston further comprises
a piston body including a piston head in slidable engagement with
the piston bore, and wherein the valve inlet of the gas relief
valve extends through the piston head.
5. The firearm of claim 4, wherein the valve housing further
comprises a plurality of outlet slots extending between the valve
bore of the valve housing and the piston bore.
6. The firearm of claim 1, wherein the gas piston comprises a
piston head movable in sliding engagement with the piston bore of
the gas cylinder, and having an axial bore in communication with
the gas relief valve, and an orifice bushing removably secured in
the axial bore of the piston head, and wherein the relief valve
comprises a valve inlet that extends through the orifice
bushing.
7. An auto-loading firearm for firing cartridges of different
lengths and/or varying load strengths, comprising: a receiver; a
barrel mounted to a forward end of the receiver, the barrel
comprising a series of gas ports arranged at spaced locations
therealong, and a chamber located at a proximal end of the barrel
to receive cartridges for firing; a bolt assembly translatable
along the receiver for loading cartridges into the chamber and
ejecting spent casings from the firearm after firing; and a gas
operating system that drives movement of the bolt assembly along
the receiver, the gas operating system comprising: a gas cylinder
having a longitudinal piston bore, and one or more ports in fluid
communication with the piston bore and at least one of the series
of gas ports of the barrel for passage of pressurized gases
generated during firing into the piston bore; a gas piston disposed
within and movable along the piston bore, the gas piston
operatively connected to the bolt assembly such that the
pressurized gases passing into the piston bore and driving the gas
piston therealong cause the bolt assembly to be driven along the
receiver for cycling the firearm; and a gas relief valve integrated
within the gas piston and movable therealong as a pressure of the
pressurized gases exceeds a desired operating level to enable
excess gases impinging on the gas piston to escape through the gas
piston and reduce pressure acting on thereon to control velocity of
the bolt assembly as it moves during cycling of the firearm,
wherein the piston bore comprises a first longitudinal piston bore
and the gas operating system further comprises a second
longitudinal piston bore laterally spaced from the first
longitudinal piston bore and extending along the gas cylinder, a
second gas piston at least partially disposed in the second
longitudinal piston bore, and a second gas relief valve disposed
internally within the second gas piston.
8. An auto-loading firearm for firing cartridges of different
lengths and/or varying load strengths, comprising: a receiver; a
barrel mounted to a forward end of the receiver, the barrel
comprising a series of gas ports arranged at spaced locations
therealong, and a chamber located at a proximal end of the barrel
to receive cartridges for firing; a bolt assembly translatable
along the receiver for loading cartridges into the chamber and
ejecting spent casings from the firearm after firing; a gas
operating system that drives movement of the bolt assembly along
the receiver, the gas operating system comprising: a gas cylinder
having a longitudinal piston bore, and one or more ports in fluid
communication with the piston bore and at least one of the series
of gas ports of the barrel for passage of pressurized gases
generated during firing into the piston bore; a gas piston disposed
within and movable along the piston bore, the gas piston
operatively connected to the bolt assembly such that the
pressurized gases passing into the piston bore and driving the gas
piston therealong cause the bolt assembly to be driven along the
receiver for cycling the firearm; and a gas relief valve integrated
within the gas piston and movable therealong as a pressure of the
pressurized gases exceeds a desired operating level to enable
excess gases impinging on the gas piston to escape through the gas
piston and reduce pressure acting on thereon to control velocity of
the bolt assembly as it moves during cycling of the firearm; and a
gas plug at least partially sealing a forward end of the piston
bore, the gas plug including a body defining a fluid flow path in
fluid communication with the gas relief valve and the one or more
ports of the gas cylinder.
9. The firearm of claim 8, wherein the body of the gas plug further
comprises one or more projections extending from a surface of the
plug body and arranged to allow fluid flow between the fluid flow
path and the gas relief valve when the gas piston is at least
partially seated against the gas plug.
10. An auto-loading firearm enabling firing of cartridges having
differing lengths and/or variable load strengths, comprising: a
receiver; a barrel coupled to the receiver and including a chamber
and at least one barrel port; a bolt assembly comprising a bolt
movable along the receiver to eject a cartridge casing and/or load
a next cartridge in the chamber after firing; a gas block including
at least one piston bore defined therealong, and at least one gas
port in fluid communication with the at least one piston bore and
the at least one barrel port to allow pressurized gases from firing
to enter the piston bore; a compensating gas piston at least
partially disposed within and movable along the at least one piston
bore; a gas pressure relief valve disposed along the gas piston and
operable in response to excess gas pressure to divert excess gases
from firing through the gas piston to reduce the gas pressure
acting on the gas piston and reduce a velocity of the bolt during
cycling of the firearm; and a gas plug at least received within and
at least partially sealing a forward end of the at least one piston
bore, the gas plug defining a fluid path therealong to enable fluid
communication between the at least one gas block port and the
relief valve.
11. The firearm of claim 10, wherein the gas plug further comprises
one or more projections extending from a surface thereof and
arranged to allow fluid flow between the fluid path and the gas
pressure relief valve with the gas piston at least partially seated
against the gas plug.
12. The firearm of claim 10, wherein the gas pressure relief valve
comprises a valve housing, a valve bore extending along the gas
piston and at least partially defined by the valve housing, and a
valve member at least partially disposed within and movable along
the valve bore.
13. The firearm of claim 12, wherein the gas pressure relief valve
further comprises a valve inlet in fluid communication with the
valve bore and the at least one piston bore, and wherein the valve
member is substantially biased against the valve inlet to at least
partially close the valve inlet.
14. The firearm of claim 13, wherein the gas piston further
comprises a piston body including a piston head in engagement with
a wall of the at least one piston bore, and wherein the valve inlet
of the gas relief valve extends through the piston head.
15. The firearm of claim 14, wherein the valve housing further
comprises a plurality of outlet slots extending therethrough
between the valve bore of the valve housing and the at least one
piston bore.
16. The firearm of claim 1, wherein the gas piston comprises a
piston head in slidable engagement with a wall of the piston bore
of the gas cylinder, the piston head comprising an axial bore in
communication with the gas pressure relief valve, and wherein the
gas piston further comprises an orifice bushing removably secured
in the axial bore of the piston head, and the gas pressure relief
valve comprises a valve inlet that extends through the orifice
bushing.
17. The firearm of claim 1, wherein the gas operating system
further comprises a pair of piston bores laterally spaced apart and
extending therealong, and a pair of gas pistons each at least
partially disposed in one of the piston bores, and each having a
gas pressure relief valve disposed internally therein.
Description
TECHNICAL FIELD
The present disclosure generally relates to a gas operating system
for firearms that allows firing of different cartridge loads for a
given shell caliber or gauge.
BACKGROUND INFORMATION
In general, automatic and semiautomatic shotguns can have
user-adjustable gas systems that allow a user to control the amount
of gas entering into and/or vented from the system. Accordingly, a
wider range of cartridge loads can be fired from a single firearm.
However, if an adjustable gas system is set for heavy loads and the
weapon is used to fire light loads, the firearm may not fully
cycle, which may require the user to manually cycle the bolt in
order to load the next round. If the adjustable gas system is set
for light loads and the weapon is used to fire a heavy load, the
bolt velocity after firing may result in improper cycling and the
weapon may suffer reduced part life for certain components.
Firearms such as the Remington Model 1187 and Versa-Max Shotguns
have self-compensating gas systems. Self-compensating gas systems
allow a range of different loads to be fired without requiring
adjustment of the gas system. However, the full range of available
cartridge loads may not be sufficiently compensated by conventional
self-compensating systems. For example, 12 shotshells can vary from
23/4'' light loads to 31/2'' heavy loads. As a result, some
self-compensating firearm gas systems may not reliably operate
light loads under all conditions, and may suffer undesirably high
bolt velocities when firing heavy magnum loads. Additionally, some
self-compensating gas systems rely on smaller cartridges, which
have a shorter length, having lighter loads and larger, longer
length cartridges having heavier loads, but in some cases smaller
cartridges can have relatively heavy loads, while longer cartridges
may not have a full or anticipated heavy load. In such a case, a
system that relies simply on the length of the shotshell or
cartridge to compensate for heavier loads might not properly
compensate for the heavier load of the shorter cartridge.
SUMMARY OF THE DISCLOSURE
According to one embodiment, the present disclosure generally
relates to a pressure compensating system for gas-operated
firearms. Such firearms can include shotguns, rifles or other long
guns or handguns, and typically can include a receiver, a firing
mechanism, a barrel having a firing chamber, one or more gas
transmission ports extending through the barrel and opening into
the firing chamber, and a gas operating system. The gas operating
system can comprise a gas block with at least one pressure
compensating gas piston movable along a gas cylinder of the gas
block. The gas cylinder defines at least one piston bore in fluid
communication with the barrel through the one or more gas
transmission ports, which can be arranged as one or more single
ports or as groups of ports located at different distances from the
chamber end of the barrel. The at least one pressure compensating
gas piston generally is at least partially received in its piston
bore and comprises a piston body having a relief valve disposed in
the interior of the piston body. The relief valve generally can
include a movable valve member received within and movable along a
valve bore formed in the piston body, and which engages and bears
against a biasing member, such as a spring or other biasing element
that provides a desired amount of biasing force urging the relief
valve toward a closed, first or inactive position. One or more
vents can be provided along the valve bore, upstream from the front
or open end of the valve bore, for enabling discharge of excess gas
through the piston body during a pressure compensation
operation.
According to one aspect of the present invention, the firearm is
capable of firing different cartridge loads, which may or may not
correspond to different cartridge lengths. The one or more ports in
the barrel can be arranged so that when shorter, lighter load
cartridges are fired, the cartridge casing is short enough so that
it does not interfere with, or render "inactive" any of the ports
in the barrel. The gases from firing therefore pass substantially
unimpeded into the gas operating system to provide the energy
needed to drive the action of the firearm. As longer cartridges
corresponding to heavier loads are fired, the cartridge case may
extend to a sufficient length within the chamber so that one or
more of the ports in the barrel are at least partially blocked,
obscured, or otherwise rendered "inactive" by the cartridge case.
The larger the number of inactive ports, the smaller the percentage
of firing gases that are used to cycle the firearm. In the case
that a shorter cartridge has a heavier load, but does not render a
sufficient number of gas ports inactive to limit the gas pressure
communicated to the gas operating system below a desired operating
level, the excess gas can cause actuation of the relief valve of
the compensating gas piston, by driving the sealing member along a
valve bore of the relief valve to a point where the excess gas can
be substantially bled off through the one or more vents located
along the valve bore to help reduce the gas pressure acting on the
compensating gas piston. Heavier load cartridges therefore can be
compensated for, whether the heavier load is associated with a
cartridge length that is sufficient to render an appropriate number
of gas ports inactive, or via the relief valve bleeding off excess
gases in the piston bore.
Other aspects, features, and details of embodiments of the present
invention can be more completely understood by reference to the
following detailed description of preferred embodiments, taken in
conjunction with the drawings figures and from the appended
claims.
According to common practice, the various features of the drawings
discussed below are not necessarily drawn to scale. Dimensions of
various features and elements in the drawings may be expanded or
reduced to more clearly illustrate the embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial sectional schematic view of a firearm having a
gas operating system according to an exemplary embodiment of the
disclosure.
FIGS. 2 and 3 are isometric views of the gas operating system and a
barrel of the firearm of FIG. 1.
FIG. 4 is an isometric view of the gas operating system with the
portions of the gas operating system inside the gas block shown in
phantom according to the exemplary embodiment of the
disclosure.
FIG. 5 is an exploded isometric view of the gas operating system of
FIG. 4.
FIG. 6A is a longitudinal cross-sectional view of the gas operating
system of FIG. 4 with the barrel of FIG. 1 schematically shown in
cross-section.
FIGS. 6B and 6C are longitudinal cross-sectional views of the gas
operating system illustrating operation of the gas operating system
during respective firing cycles.
FIG. 7 is a transverse cross-sectional view of the gas operating
system illustrating operation of the gas operating system during a
firing cycle.
FIG. 8 is an isometric view of a gas cylinder plug according to an
alternative embodiment of the present disclosure.
FIG. 9 is a front end view taken in cross-section of the gas
cylinder plug of FIG. 8.
FIG. 10 is a longitudinal cross-sectional view of the gas operating
system utilizing the gas cylinder plug of FIG. 8.
DETAILED DESCRIPTION
Referring now to the drawings in which like numerals indicate like
parts throughout the several views, FIGS. 1-7 generally illustrate
one embodiment of a gas operating system according to the
principles of the present disclosure for use in a firearm, such as
an autoloading shotgun or other similar type of gas operated
firearm. However, it will be understood that the principles of the
barrel mounting and retention device of the present disclosure can
be used in various types of firearms including rifles and other
long guns, handguns, and other gas-operated firearms such as M4,
M16, AR-15, SCAR, AK-47, HK416, ACR and the like. The following
description is provided as an enabling teaching of exemplary
embodiments; and those skilled in the relevant art will recognize
that many changes can be made to the embodiments described. It also
will be apparent that some of the desired benefits of the
embodiments described can be obtained by selecting some of the
features of the embodiments without utilizing other features.
Accordingly, those skilled in the art will recognize that many
modifications and adaptations to the embodiments described are
possible and may even be desirable in certain circumstances, and
are a part of the invention. Thus, the following description is
provided as illustrative of the principles of the embodiments and
not in limitation thereof, since the scope of the invention is
defined by the claims.
The invention as exemplified by the embodiment discussed below
generally is directed to a gas operating system for autoloading
firearms. The gas operating system allows a user to fire different
loads for a given cartridge or shell caliber or gauge, while
avoiding undesirably high bolt velocities caused by firing
excessive or higher pressure loads, while also ensuring that the
weapon cycles fully when firing lighter loads. The gas operating
system can control the amount of gas tapped from the barrel that is
used to operate the firearm action by controlling a number of
"active" ports in the firing chamber. An "active" port may be
generally defined as a gas bleed port that is at least partially
unobstructed by a cartridge case and therefore available to tap
gases generated during firing. According to the present invention,
the gas ports may be located adjacent or at least partially within
the chamber area of the barrel. Cartridge cases of differing sizes
and loads can selectively cover and render gas ports inactive
according to the lengths of the cartridge cases. Additionally, as
shown in the figures, the gas operating system can include a relief
valve for relieving excess pressure exerted on a gas piston of the
gas operating system during operation of the firearm.
FIG. 1 is a partial sectional view schematically illustrating a
gas-operated firearm 20 incorporating a gas operating system 22
according to one embodiment of the invention. The firearm 20
generally includes a barrel 24 having a proximal end 26 with a
cartridge firing chamber 28 that is connected with a cylindrical
portion 30 of the barrel 24 by a conical constriction portion 32.
An example cartridge C is shown chambered within the chamber 28.
While the cartridge C is generally illustrated as a shotshell,
other types of ammunition cartridges also can be used with the gas
operating system of the present invention. The barrel 24 and the
gas operating system 22 can be mounted to a forward end of a
receiver 33 so that the chamber 28 of the barrel 24 and a portion
of the gas operating system are in communication with a bolt 34.
The bolt 34 is translatable along the receiver 33 in response to
actuation of the gas operating system 22, to cause the bolt to
translate along the receiver, for ejecting a spent shell casing
from the firearm, and thereafter will be pushed forwardly along the
receiver to load a new cartridge from a magazine (not shown) into
the chamber 28. In the exemplary illustrated embodiment, the bolt
34 has a rotating head 40 which may be, for example, of the type
described in U.S. Pat. No. 4,604,942, the disclosure of which is
hereby incorporated by reference as if presented herein in its
entirety. The bolt and receiver also could be otherwise shaped,
arranged, and/or configured without departing from the
disclosure.
Actuation and operation of the gas operating system 22 is driven by
combustion gases from firing of the cartridge. These gases are
supplied to the gas operating system from a plurality of gas
transmission ports formed in the gas operating system and along the
barrel 24, collectively indicated by the reference numbers 36 and
38, respectively (see FIGS. 1, 4 and 6A). As schematically
indicated in FIG. 6A, each of the gas transmission ports 36 of the
gas operating system 22 generally can be aligned with a
corresponding one of the ports 38 in the barrel 24. Alternatively,
the barrel and the gas operating system can have different numbers
of gas transmission ports. The gas transmission ports 36, 38 allow
gases generated during firing to be tapped from the chamber 28 and
directed to the gas operating system 22 to cycle the firearm 20
(FIG. 1). The gas transmission ports 36, 38 could be otherwise
shaped, arranged, and/or configured without departing from the
disclosure. For example, in one embodiment, the barrel could have
two gas transmission ports 38 that are aligned with respective gas
transmission ports 36 of the gas operating system, and additional
gas ports 36 in the gas operating system are closed off by the
exterior surface of the barrel 24.
The barrel 24 and the gas operating system 22 are further shown in
FIGS. 2 and 3. In the illustrated embodiment, the gas operating
system 22 includes a gas cylinder or gas block 42 with a concave
upper surface 44 (FIGS. 4 and 5), and a pair of compensating gas
pistons 46, with gas cylinder plugs 48 at a front or downstream end
of the gas block. The underside of the proximal end 26 of the
barrel 24 rests on the concave upper surface 44 of the gas block
42, with the gas block 42 being mounted, brazed or otherwise
attached to the underside of the barrel 24, with at least some or
all of the gas transmission ports 36, 38 aligned and in fluid
communication. In one embodiment, an alignment pin 49 (FIG. 1) can
be received in corresponding recesses or bores 51a/51b in the
exterior surface of the barrel 24 and the concave upper surface 44
of the gas block 42 to help position the gas block along the
exterior surface of the barrel so that the gas transmission ports
36, 38 are properly aligned. Alternatively, the gas block 42 could
be otherwise affixed to the barrel or integrally formed with the
barrel.
As shown in FIGS. 4 and 5, the gas block 42 can include a pair of
longitudinal sections 50 that are laterally spaced by a central
section 52. In the illustrated embodiment, the longitudinal
sections 50 generally are mirror images of one another. Each of the
longitudinal sections 50 includes a longitudinal piston bore 54 for
receiving a movable pressure compensating gas piston 46 therealong,
and which may be sealed at its forward end by a gas cylinder plug
48. Other alternative arrangements for enclosing the piston bores
of the gas block also can be used, for example, a diverter cap
having a tapered or otherwise shaped base or stem, which can
further include one or more gaskets to help seal the piston bores.
Alternatively, the piston bores could be blind bores formed from
the rear face 55a of the gas block so that an integral wall of the
gas block 42 at the forward end 55b of the gas block 42 seals the
forward ends of the piston bores. Each of the piston bores 54 is in
communication with the gas transmission ports 36, which are aligned
in the longitudinal direction in the illustrated embodiment.
Alternatively, the piston bores 54 can be in communication with any
suitable number of gas transmission ports 36, and the gas
transmission ports can be otherwise arranged without departing from
the disclosure. Each of the piston bores 54 also can be in
communication with a relief vent 56 (FIGS. 3 and 4) proximate to
the rear ends of the longitudinal sections 50. In the illustrated
embodiment, the relief vents 56 can be spaced a distance Dl from
the rear end of the gas block 42 (FIG. 4). The gas block 42 could
be otherwise shaped, arranged, and/or configured without departing
from the disclosure.
According to one aspect of the invention, the plurality of gas
transmission ports 36 in the gas block 42 are in fluid
communication with the plurality of gas transmission ports 38 in
the barrel 24 (e.g., see FIG. 6A), and allow cartridge loads of
different "strength" to be fired from the firearm 20. A firearm
configured so that cartridge casings of different lengths and
corresponding load strengths affect the number of active gas
transmission ports in the barrel is described in U.S. Pat. No.
8,065,949, the disclosure of which is hereby incorporated by
reference as if presented herein in its entirety. For example, a
relatively longer cartridge with a larger load can at least
partially cover one or more of the gas transmission ports 38 upon
firing of the firearm 20, while a shorter cartridge with a smaller
load generally may not cover any of the gas transmission ports 38
in the barrel 24. Closing selected gas transmission ports 36, 38
restricts gas flow from the barrel 24 to the gas block 42 when the
longer cartridge is fired to help compensate for the higher gas
pressure resulting from the larger load of the longer cartridge.
Accordingly, longer cartridge casings can render one or more gas
transmission ports 38 inactive. An inactive gas port is either
wholly or partially ineffective in transmitting gases generated
during firing to the piston bores 54, and therefore may not fully
contribute to the rearward forces on the compensating gas pistons
46 that force the bolt rearwardly.
As shown in FIGS. 4, 5, and 6A, the gas transmission ports 36 are
arranged along the length of the longitudinal sections 50 of the
gas block 42 and generally extend through the cylinder from the
concave upper surface 44 to the piston bores 54. The outlines of
the respective gas transmission ports 36 in each of the
longitudinal sections 50 are shown in phantom in FIG. 4. In the
illustrated embodiment, the gas transmission ports 36 extend
generally radially from the concave upper surface 44 to be in fluid
communication with the respective piston bores 54. Alternatively,
the gas transmission ports 36 may be formed in the gas block 42 at
various angular orientations. As shown schematically in FIG. 6A,
the gas transmission ports 38 are aligned with the gas transmission
ports 36 in the gas block 42 and extend through the wall of the
barrel 24 to be in fluid communication with the chamber 28. In one
embodiment, the gas transmission ports 38 can extend at an angle
with respect to the radial direction in the illustrated embodiment.
For example, the gas transmission ports 38 can extend generally
rearwardly from the interior surface of the barrel 24 to the
exterior surface of the barrel. Alternatively, the gas transmission
ports 38 can extend at any suitable angle. The gas transmission
ports 36, 38 could be otherwise shaped, arranged, and/or configured
without departing from the disclosure. For example, any number,
combination, and/or arrangement of gas transmission ports may be
formed in the barrel and the gas block in order to accommodate
firing of a wide variety of cartridge loads.
In the illustrated embodiment, each of the gas cylinder plugs 48 is
received in the respective piston bores 54 at the forward end of
the gas block 42. As shown in FIG. 5, each gas cylinder plug 48
includes a threaded head 58, an O-ring seat 60, and a diverter
portion 62. The threaded head 58 can be threaded for being
threadedly engaged with a threaded portion 59 of the piston bore 54
at the forward end 55b of the gas block (FIG. 6A). Additionally, as
shown in FIG. 4, the head can include a socket 64 for engaging a
hex key or other tool. The O-ring seat 60 comprises an annular
recess for receiving an O-ring 66 or other sealing feature that
helps to seal the piston bores 54 at the forward end of the gas
block 42 (FIG. 6A). The threaded head 58 can have a diameter that
is a relatively close fit in the piston bore 54 and a larger cap
portion 65 that engages the forward surface 55b of the gas block 42
when the gas cylinder plug 48 is fully screwed into the forward end
59 of the piston bore 54.
As shown in FIGS. 4, 5, and 6A, the diverter portion 62 is
generally cylindrical with a smaller diameter than the piston bore
54, forming an annular space 68 (FIG. 6A) between the interior
surface of the piston bore 54 and the exterior surface of the
diverter portion 62. As shown in FIG. 6A, the diverter portion 62
extends into the piston bore 54 past the gas transmission ports 36
so that the annular space 68 is in fluid communication with the gas
transmission ports 36, thus enabling the gases to flow along the
diverter portion 62 and into contact/driving engagement with the
piston 46. Additionally, a rearward stop end 69 of the diverter
portion 62 provides a forward stop for the compensating gas piston
46 in the piston bore 54 that is to the rear of the gas
transmission ports 36. Accordingly, in one embodiment, the
compensating gas piston 46 will not block the gas transmission
ports 36. The gas cylinder plug 48 could be otherwise shaped,
arranged, and/or configured without departing from the disclosure.
For example, the diverter portion 62 could have a frustoconical
shape or any other suitable shape, or the diverter portion 62 could
be omitted.
As shown in FIG. 5, the compensating gas pistons 46 each include an
elongate cylindrical piston body 70 having a plurality of spaced
annular cleaning ribs 72 and a head 74. The compensating gas
pistons 46 are received and longitudinally translatable within a
rear end 75 of the respective piston bores 54 and are biased toward
the stop end 69 of the diverter portion 62 of the gas cylinder plug
48 (FIG. 6A) by a spring (not shown), for example. The piston head
74 can be sized for a snug, slidable fit in the piston bore 54 so
that little or no gas can move between the piston head 74 and the
inner surface of the piston bore 54. As schematically shown in FIG.
1, the piston body 70 is in communication with the forward end of
the bolt 34 in the receiver 33 so that the bolt is actuated when
the compensating gas pistons 46 translate rearwardly.
In the illustrated embodiment, each of the compensating gas pistons
46 includes an internal pressure relief valve 80 to help reduce
excess pressure on the piston head 74 in the respective piston bore
54. As shown in FIGS. 5 and 6A, each compensating gas piston 46
comprises a valve housing 81 extending from the piston head 74. The
valve housing 81 of the piston body 70 defines a longitudinal valve
bore or passage 82 that receives a valve spring 84, a movable valve
member 86 (here shown as a ball bearing), and an orifice bushing
88. Accordingly, the respective piston bodies 70 of the
compensating gas pistons 46 act as housings for the respective
relief valves 80. The orifice bushing 88 is received in the valve
bore 82 at the head 74 of the compensating gas piston 46 and
defines a valve inlet 90 in fluid communication with the piston
bore 54 and the valve bore 82 when the internal relief valve 80 is
open. In one embodiment, the valve inlet 90 is generally aligned
with a longitudinal axis CP of the valve bore 82 and the piston
body 70 (FIG. 6A). The orifice bushing 88 can be threadedly or
otherwise releasably engaged with the valve bore 82 so that the
orifice bushing can be removed. A hex socket or another suitable
feature also can be incorporated into the valve inlet 90 to
facilitate tightening the orifice bushing 88 in the valve bore with
a tool (not shown). Alternatively, the orifice bushing could be
press fit and/or secured with adhesive in the valve bore 82, and
further, the orifice bushing may be secured, attached to, or
otherwise assembled with the piston by orbital riveting,
microwelding, or other attachment mechanism.
As shown in FIGS. 6A-6C, the valve member 86 and the valve spring
84 are movable along the valve bore 82 during operation, and
further can be removable from the valve bore when the orifice
bushing 88 is removed (FIG. 5) for cleaning the valve bore 82
and/or replacing the valve member 86, the valve spring 84, and/or
the orifice bushing 88. In addition, while the relief valve has
been illustrated in the drawings as including a ball moving against
the spring, it will be understood that other constructions also can
be used. For example, the valve member could comprise a piston rod
or other similar member movable along the valve bore in bearing
engagement with a spring, diaphragm, or other bearing member.
As shown in FIGS. 5, 6C, and 7, the relief valve 80 can include a
series of outlet slots 92 (here shown as 4 outlet slots although
less or more slots or other outlets can be used) formed in the
housing 81. The outlet slots 92 are in communication with the valve
bore 82 and disposed between the head 74 of the compensating gas
piston 46 and the forward annular rib 72. As shown in FIG. 6A, the
valve spring 84 biases the valve member 86 forwardly in the valve
bore 82 against the orifice bushing 88 to block the valve inlet 90.
When excess gas pressure in the piston bore 54 rises to a level
sufficient to overcome the spring force of the valve spring 84, the
gases urge the valve member 86 rearwardly away from the orifice
bushing 88. This opens the valve bore 82 to passage of the gases
through the valve inlet 90 into the valve bore 82, and then out
through the outlet slots 92 into the portion of the piston bore 54
that is to the rear of the head 74 of the compensating gas piston
46 as indicated in FIG. 6C. As each pressure compensating gas
piston 46 likewise is moved rearwardly along its piston bore 54,
the outlet slots 92 can be brought into fluid communication with
the relief vent 56 of the gas block 42 (FIG. 7), whereby the excess
gases can escape from the gas block. The compensating gas pistons
46 and/or the relief valves 80 could be omitted or otherwise
shaped, arranged, and/or configured without departing from the
disclosure. For example, the ball bearing 86 could be replaced with
any suitable poppet or piston having any suitable shape, such as a
cylindrical, hemispherical, conical, frustoconical, etc.
In the illustrated embodiment, the compensating gas pistons 46
provide relief valves 80 without adding bulk to the gas operating
system 22. Additionally, the gas operating system 22 can be easily
disassembled by removing the gas cylinder plugs 48 and the
compensating gas pistons 46 from the piston bores 54. In one
embodiment, each of the gas cylinder plugs 48 is easy to remove,
such as with the hex key, so that the gas cylinder plugs 48 and the
compensating gas pistons 46 can be removed from the respective
piston bores 54 through the forward ends 59 of the piston bores
without disassembling the gas block 42 from the barrel 24.
Accordingly, the gas cylinder plugs 48, the compensating gas
pistons 46, and/or the piston bores 54 can be cleaned and/or the
gas cylinder plugs 48 and/or the compensating gas pistons 46 can be
replaced without disassembling other portions of the firearm.
In operation, a shell C is loaded into the chamber 28 and the bolt
34 is closed, chambering the shell C as shown in FIG. 1. The bolt
head 40 locks to the barrel 24 and helps to secure the cartridge C
in the chamber 28 after the shell C is fired. Generally, the shell
C is fired by activating a firing mechanism, such as by pulling a
trigger to release a striker, which in turn hits the cartridge
primer (not shown). The primer is ignited and in turn ignites the
main powder charge in the shell C. As pressure builds in the
cartridge case and the chamber 28, a wad and shot column of the
shell C travels down the barrel 24.
As the shot column travels down the barrel 24, a percentage of the
high pressure firing gases in the barrel 24 is tapped and is
introduced into the gas block 42. In one embodiment, when the
cartridge C is fired, the case of the cartridge C assumes an
extended form (not shown) as the cartridge casing unrolls. In one
example, the extended cartridge form may not cover or otherwise at
least partially obstruct any of the ports 38 in the barrel 24. All
ports 38 therefore remain active to transmit gases through the
respective gas transmission ports 36 in the gas block 42. The gases
transmitted through the gas transmission ports 36 are transmitted
into the piston bores 54 and force the compensating gas pistons 46
rearward against the bolt 34. The gases generated during firing are
therefore able to flow through all of the ports 36, 38 (i.e., all
ports are active) to the compensating gas pistons 46 in the piston
bores 54, which provides the energy to unlock the bolt 34 and to
propel the bolt rearwardly in the receiver.
As the bolt 34 travels rearwardly, the spent case C is pulled from
the chamber 28 and ejected from the firearm 20. The bolt 34 travels
to the rear of the receiver 33, which also compresses an action
spring (not shown). If a next shell is present, such as from a
magazine, the bolt 34 is released from the rear position and is
propelled forward by the stored energy in the action spring. As the
bolt 34 travels back toward the barrel 24, the new shell is fed
into the chamber 28 and the bolt head 40 locks to the barrel 24.
The cycle repeats when the trigger is again pulled.
In another example, when a longer cartridge (not shown) generally
corresponding to a heavier load shell is loaded into the chamber
28, and is fired, the case of the longer cartridge can at least
partially cover one or more of the ports 38 in the barrel 24,
rendering them inactive. The gases generated during firing are
therefore either wholly or partially blocked from passing into the
gas block 42 through the corresponding ports 36 in the gas block 42
that are aligned with the inactive gas ports 38. The gas
transmission ports 38 that are farther down the barrel 24 remain
active, and the firing gases are allowed to pass through the
corresponding ports 36 and into the piston bores 54. The gases
transmitted to the piston bores 54 provide the energy required to
force the compensating gas pistons 46 rearwardly to cycle the
firearm 20, as discussed above. However, having fewer active gas
ports 38 can help to compensate for the additional firing gases
that may be produced by a heavier load shell.
In some cases, the cartridge load strength may not correlate with
the length of the cartridge. For example, a relatively short
cartridge can have a relatively large load strength and can produce
higher gas pressure in the chamber 28 than desired for operation of
the gas operating system 22 while the short length of the cartridge
might not cover the gas transmission ports 38 upon firing.
Accordingly, a relatively high gas pressure can be communicated
through the gas transmission ports 36, 38 to the piston bores 54
and drive the compensating gas pistons 46 rearward with more force
than desired. However, the relief valves 80 in the compensating gas
pistons 46 can help excess gases to escape from the piston bores 54
through the respective piston bodies 70 to reduce the forces on the
respective heads 74 of the pressure compensating gas pistons.
Particularly, for each of the longitudinal sections 50, the gases
flow from the gas transmission ports 36 and enter the annular space
68 between the diverter portion 62 of the gas cylinder plug 48 and
the interior surface of the piston bore 54. As shown in FIG. 6A,
the compensating gas piston 46 is biased against the stop end 69 of
the diverter portion 62, and the piston head 74 blocks the gases
from passing to the rear of the diverter portion 62 in the piston
bore 54. Additionally, the threaded head 58 of the gas cylinder
plug 48 and the O-ring 66 can generally seal off the forward end 59
of the piston bore 54 so that gases flowing into the piston bore 54
through the gas transmission ports 36 build up in the annular space
68. As the pressure in the annular space 68 increases, the gases
push against the head 74 to push the compensating gas piston 46
rearward. As the head 74 moves away from the rear end of the gas
cylinder plug 48, the gases can flow into the valve inlet 90 and
push against the valve member 86. If the gas pressure is below a
desired operating pressure for the firearm (e.g., a gas pressure
that is selected to be low enough to help avoid undue wear and/or
misalignment of the bolt 34, receiver 33, compensating gas pistons
46, and/or other features of the firearm), the pressure does not
overcome the spring force of the valve spring 84 and the valve
member 86 remains seated against the orifice bushing 88.
Accordingly, the gas pressure can force the piston head 74 rearward
so that the compensating gas piston 46 moves rearward in the piston
bore 54 as shown in FIG. 6B.
In the illustrated embodiment, the piston body 70 moves rearwardly
out of the piston bore 54 and into the receiver 33 (FIG. 1) to
actuate the bolt 34. In one embodiment, the piston head 74 remains
in the piston bore 54 through the length of travel of the
compensating gas piston 46. In one embodiment, the piston head 74
is disposed forwardly of the relief slot 56 in the piston bore 54
when the compensating gas piston 46 stops retracting (e.g., when
the bolt 34 is fully retracted in the receiver 33). Accordingly,
the piston head 74 does not block the relief vent 56. When the
compensating gas piston 46 is returned to the position of FIG. 6A
with the piston head 74 abutting the stop end 69 (e.g., by the bolt
34 or by a biasing spring, not shown), the gases remaining in the
piston bore 54 can be exhausted through the gas transmission ports
36, 38. In another embodiment, the piston head 74 can translate to
a position that is to the rear of the relief vent 56 when the
compensating gas piston 46 is in its rearmost position.
Accordingly, gases in the piston bore 54 can exit the piston bore
through the relief vent before the compensating gas piston 46 is
returned to the position of FIG. 6A.
If the pressure of the gases acting on one or both of the gas
compensating pistons 46 is above a predetermined, desired operating
pressure, once the gas pressure forces the respective gas
compensating piston 46 rearwardly so that the piston head 74 moves
away from the stop end 69 of the gas cylinder plug 48, the gas
pressure on the valve member 86 overcomes the spring force of the
valve spring 84 and the valve member 86 is moved away from the
orifice bushing 88 in the valve bore 82 as shown in FIG. 6C. The
excess gases then can flow through the valve inlet 90 into the
valve bore 82 until the pressure on the valve member 86 decreases
to the desired operating pressure and the valve spring 84 forces
the valve member against the orifice bushing 88 to close the valve
inlet 90 (FIGS. 6A and 6B). With the relief valve 80 open, the
gases can escape the valve bore 82 through the outlet slots 92 into
the portion of the piston bore 54 behind the head 74, and the
excess gases can escape the piston bore through the relief slots 56
(FIG. 7).
In the illustrated embodiment, the gas operating system 22 includes
two compensating gas pistons 46. In a different embodiment, one or
both of the compensating gas pistons 46 could be otherwise
configured (e.g., the internal relief valve 80 could be omitted).
Additionally, the gas operating system could comprise any suitable
number of compensating gas pistons 46 or other pistons, and the gas
block 42 could include a corresponding number of longitudinal
sections 50 and piston bores 54 without departing from the
disclosure. Other features of the gas operating system 22 and the
firearm 20 could be otherwise shaped, arranged, and/or configured
without departing from the disclosure.
According to one aspect of the present invention, the gas operating
system renders a firearm capable of firing a wide range of
cartridges/shot loads without requiring active adjustment of the
firearm. The volume or flow of gases transmitted for cycling the
firearm are instead passively or automatically adjusted according
to a length of a cartridge or shell casing used. Any number and/or
combination of ports may be formed in the barrel, and a series of
corresponding ports formed in the gas cylinder, in order to
accommodate firing of a wide variety of cartridge loads.
Additionally, the gas operating system can compensate for higher
gas pressures or volumes regardless of the length of the cartridge
or shell casing, wherein the relief valves can help to further
reduce gas pressure in the gas operating system by bleeding off
excess gas.
As illustrated in FIGS. 8-10, in an alternative embodiment, the gas
operating system may include a gas cylinder plug or plugs 148 with
one or more ports, holes, openings, channels, or other flow paths
170 defined therein, and configured to direct or enable fluid
communication between the gas transmission ports 36, 38 of the
firearm barrel and the relief valves 80 provided in each piston
head 74 when the piston heads are seated against the plugs 148. The
gas cylinder plugs 148 may generally include a plug body 149 having
a rear or distal end 151 with the one or more flow paths 170
defined therein. The plug body 149 further optionally may include a
diverter portion 162 formed therewith, which can define a diverter
flow path 163 (FIG. 10) along an outer circumferential surface 144
of the plug body 149. This diverter flow path 163 may be in fluid
communication with one or more of the flow paths 170. As further
shown in FIGS. 8-9, each flow path 170 can include one or more
inlets, apertures, or other openings 172 adapted or configured to
receive gases from the gas transmission ports 36, and direct such
gas flows to a control recess, or other opening 174 in fluid
communication with the relief valves 80 of the piston heads, so as
to provide one or a series of pathways for fluid communication
between the gas ports 36, 38 (FIG. 10) and the relief valves 80
through the plug body 149.
As shown in the embodiment illustrated in FIGS. 8-9, a series of
inlets 172 can be defined in an outer circumference surface of the
plug body 149, to provide for multiple paths or channels 170 along
the plug body 149. Such flow paths can enable and/or facilitate
release of excess gas pressure in the gas operating system through
the relief valves, even when the piston heads 74 are seated against
the gas plugs 148; and thereby can provide for enhanced or faster
dissipation or reduction of gas pressures in the system at a time
when they are at a maximum, i.e., after firing, to further help
reduce undesirably high bolt velocities, reduce wear and prolong
the lifetime of the firearm components.
In one example, the flow paths or channels 170 (FIG. 8) can be
defined between a series of spaced projections 180 extending, or
protruding, from a distal surface 146 of the plug body 149 facing
the forward end of the piston and the gas relief valve defined
therein. Each projection 180 can include a projection body 182,
side walls 184, and a top surface 186, with the fluid communication
ports or channels 170 formed or defined between the side walls 184
of adjacent projections 180. When the piston heads 74 (FIG. 10) are
seated against their corresponding gas plugs 148, each piston head
74 can be contacted by the projections 180, so as to provide or
create a space or series of spaces 176 between the distal surface
146 of the plug body 149 and the relief valves 80 of the piston
heads 74, thereby preventing the front surface 146 from obstructing
or otherwise restricting gas flow into the relief valves 40. As a
result, expanding gases exiting the barrel 24 upon firing can pass
through transmission gas ports 36, 38, along the body of the gas
plug, and subsequently can be diverted into or otherwise flow
through the fluid ports or channels 170 so as to impact and/or pass
into the relief valves 80 when the piston heads 74 are seated
against the plugs 148. It additionally will be understood that
embodiments of the present disclosure are not limited to the
configuration of ports or channels 170 shown in FIGS. 8-10 and may
include any configuration or arrangement of ports, holes, openings,
channels, or other fluid communication paths that allow for direct,
or indirect, fluid communication between the gas ports and the
relief valves.
The foregoing description generally illustrates and describes
various embodiments of the present disclosure. It will, however, be
understood by those skilled in the art that various changes and
modifications can be made to the above-discussed firearm and gas
operating systems for a firearm without departing from the spirit
and scope of the invention as disclosed herein, and that it is
intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as being
illustrative, and not to be taken in a limiting sense. Furthermore,
the scope of the present disclosure shall be construed to cover
various modifications, combinations, additions, alterations, etc.,
above and to the above-described embodiments, which shall be
considered to be within the scope of the present invention.
Accordingly, various features and characteristics of the systems
and methods as discussed herein may be selectively interchanged and
applied to other illustrated and non-illustrated embodiments of the
invention, and numerous variations, modifications, and additions
further can be made thereto without departing from the spirit and
scope of the present invention as set forth in the appended
claims.
* * * * *
References